The width of crop mowing machines, such as mower-conditioners, self-propelled windrowers, and the like have been increasing in order to form sufficiently large windrows of crop to meet the capacity of modern balers and forage harvesters. These wider mowing machines have presented the challenge to designers of how to converge the mowed crop. One of the solutions applied to platforms having rotary cutter bars, for example, is to provide powered crop converging drums. U.S. Pat. No. 6,581,362, granted to Rosenbalm et al. on 24 Jun., 2003 discloses such a platform.
The prior art platform has the disadvantage that crop can get forced under those converging drums, which are offset to the rear from the cutter bar centerline, when crop is converging to the crop discharge zone where the conditioner is located. When crop gets trapped under one or the other, or both of, the rearwardly offset converging drums, further crop can be carried around to the rear of the drum(s) and get trapped between the drum(s) and the bulkhead of the platform. This trapped crop can cause plugging of the drum(s), i.e., the crop can wedge so tight that the drum(s) is (are) prevented from rotating. This can result in the failure of components of the powered drum drive system.
Another drawback of the prior art platform is that crop, carried by the first cutter disc directly in front of the crop discharge zone defined between opposite inner side walls to which the conditioner is mounted, will sometimes hairpin on the fronts of these inner side walls. This crop build-up can grow in size until it interferes with crop flow or causes plugging of the converging drums.